very honestly it is not possible that in 2022 almost everyone will be using bitcoin, to me just a few percent people will be using it but they will also use fiat currency because even in 2022 every thing will not be available in bitcoin, to me it will take decades and will take generations when most of the people will be using bitcoin for their shopping and for other activities.
Even for 1,000 years from now my prediction is that people will still use paper money and not bitcoin alone. The should live together and they will help all the people for easy transaction, they are unique so they have different uses.